This invention relates generally to improvements in bottled water coolers for use in providing a chilled supply of water for drinking, cooking, etc. More particularly, this invention relates to a bottled water cooler of the type having a thermoelectric module for chilling the water supply, wherein the thermoelectric module includes air circulation means for circulating a flow of cooling air over a heat sink, and further wherein the water cooler includes means for prompting timely cleaning or replacement of an air filter associated with the air circulation means to insure continued energy-efficient water chilling.
Bottled water coolers are well known in the art for containing a supply of relatively purified water in a convenient manner and location ready for substantially immediate dispensing and use. Such water coolers commonly include an upwardly open reservoir adapted to receive and support a water bottle of typically three to five gallon capacity in an inverted orientation such that bottled water may flow downwardly into the cooler reservoir. A spigot or faucet valve on the front of a cooler housing is operable at any time to dispense the water in selected amounts. Such bottled water coolers are widely used to provide a clean and safe source of drinking water, especially in areas wherein the local water supply may or is suspected to contain undesired levels of harmful contaminants. Alternative so-called point-of-use water coolers are also known in the art wherein the cooler is connected to a water supply line and includes water filtration and/or purification means such as a reverse osmosis unit for purifying water supplied to the cooler reservoir.
In many water coolers of the type described above, it is desirable to refrigerate at least a portion of the water within the cooler reservoir to a relatively low temperature to provide a highly pleasing and refreshing source of drinking water. However, refrigeration equipment for such water coolers has typically comprised conventional compressor-type mechanical refrigeration systems which undesirably increase the overall cost, complexity, size, operational noise level, and power consumption requirements of the water cooler. Alternative cooling system proposals have suggested the use of relatively compact and quiet thermoelectric heat transfer modules, such as the systems shown and described in U.S. Pat. Nos. 5,072,590 and 6,003,318. In such proposals, a thermoelectric module is mounted with a cold side in heat transfer relation with water within the cooler reservoir, and a hot side of the module is associated with a heat sink for dissipating heat drawn from the water. A cooling fan is normally provided for circulating air over the heat sink for improved heat transfer and energy-efficient operation.
While thermoelectric chiller systems are relatively simple in construction and quiet in operation, such systems nevertheless exhibit certain potential disadvantages which have limited their widespread adoption and use. More specifically, and by way of one important example, the chilling capacity of the thermoelectric module is relatively small in comparison with the chilling capacity of a conventional mechanical refrigeration system, resulting in a slower recovery time to provide chilled water following a large withdrawal or several successive withdrawals of water from the cooler reservoir. To minimize the impact of this reduced chilling capacity, it is essential to operate the thermoelectric module in a mode for substantially optimized heat transfer to and heat dissipation from the heat sink at all times. However, airborne contaminants present in the circulatory air flow passed over the heat sink can accumulate rapidly as a coating on the exterior surfaces of the heat sink to obstruct efficient convective heat transfer to the circulatory air flow, resulting in inefficient and slower chilling of the water within the cooler reservoir. Air filters have been provided to filter the circulatory air flow passed over the heat sink, as described in U.S. Pat. No. 6,033,318. However, such air filters also become clogged with collected airborne contaminants over a relatively short period of time, and must be regularly cleaned or replaced to avoid significant air flow reduction and associated reduced heat transfer efficiency.
Existing water coolers of the type having a thermoelectric chiller module, and further including air circulation means for delivering a flow of filtered air over the exterior surfaces of a heat sink, have not provided an effective means for monitoring the condition of the associated air filter to insure regular inspection, cleaning or replacement of the air filter. Instead, air filter cleaning or replacement have been performed sporadically at best, with the result that the thermoelectric chiller module is often operated in an inefficient manner for extended periods of time.
The present invention overcomes these problems and disadvantages by providing a filter monitor system designed to provide a convenient yet readily visible signal that a filter service interval has expired, and that the air filter needs to be removed from the water cooler for appropriate cleaning or replacement.
In accordance with the invention, a filter monitor system is provided in a bottled water cooler for automatically tracking a filter service interval, and for indicating that filter cleaning or replacement is required for continued efficient cooler operation. The filter monitor system is particularly designed for use with a water cooler of the type having a thermoelectric chiller module for chilling at least a portion of water contained within a cooler reservoir, in combination with air circulation means for delivering a filtered air flow over the exterior surfaces of a heat sink to dissipate heat collected from water contained within a cooler reservoir. The filter monitor system indicates when an air filter, provided as part of the air circulation means, should be removed from the water cooler for inspection, cleaning or replacement.
In a preferred form of the invention, the thermoelectric chiller module is mounted with a cold side thereof in heat transfer relation with water contained within the cooler reservoir. A hot side of the thermoelectric chiller module is positioned in heat transfer relation with a heat sink having an extended exterior surface area, whereby heat energy is transferred by the chiller module from the water within the reservoir to the heat sink. The air circulation means comprises a fan for delivering or otherwise causing a flow of cooling air to pass over the exterior surface area of the heat sink for collecting and dissipating heat energy therefrom. The air filter is mounted on a filter frame which is removably positioned for filtering this fan-induced air flow.
A reset switch is mounted on the water cooler in a position to be contacted and reset by the filter frame each time the air filter is mounted on the water cooler. The reset switch activates a timer which tracks a predetermined filter service interval, such as about thirty days, and then energizes a service signal as by illuminating a light visible from the exterior of the water cooler to indicate that it is time to remove the air filter for inspection, cleaning or replacement. In one form, the timer may also be coupled to a deactivation switch for turning the cooler off in the event that the air filter is not removed from the cooler within a predetermined maximum filter service time, such as about sixty days.
Other features and advantages of the invention will become more apparent from the following detailed description, taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the invention.